Transcript Chapter 5

Chapter 5
Plant Reproduction
When organisms duplicate themselves, the
process is termed reproduction.
 When production is deliberately controlled
and manipulated, it becomes propagation.
 The reproduction of plants through the
formation of seeds is called sexual
reproduction.
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Asexual reproduction is a vegetative
process that eliminates genetic variation.
 Mitosis is the normal division of a cell
nucleus that occurs as a plant grows,
enlarging from embryo to maturity.
 In a natural world, plants reproduce both
sexually and asexually.
 Sexual propagation utilizes seeds.
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Scarification is the breaking of a seed coat
otherwise impervious to water to permit
water uptake by the embryo.
 Stratification is the exposure of the seeds
to low temperatures.
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Different methods of Scarification
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When many plants are reproduced asexually from a
single plant, the group of new plants is termed a
clone.
Plants of horticultural importance that are
propagated almost totally by asexual means are
termed clonal varieties. They are a type of cultivar.
Runners are stems that grow along the ground and
form new plants at one or more of their nodes.
Stolons are aerial shoots that take root after coming
into contact with the soil.
Certain plants produce new shoots from
adventitious buds that develop on the
roots called sucker shoots.
 In layering, roots develop on a stem that
is still attached to the parent plant.
 Propagation by stem cuttings is the most
common means of
reproducing plants asexually.
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A plants external appearance is also know
as its phenotype.
 A plants genetic composition is also know
as its genotype.
 Gregor Mendel took two strains of garden
pea’s that were notably different in height
and conducted experiments on them.
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When the sexual reproduction process is
controlled by the deliberate actions of
human beings, plant breeding results and
a specialized science, plant genetics, takes
effect.
 Mutations are spontaneous changes in the
genetic structure of a plant.
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Different types of mutations
Asexual propagation techniques:
 Runners
 Stolons
 Sucker
shoots
 Layering
 grafting